The Revised New General Catalogue (RNGC) is a big list of over 13,000 objects in space, like stars and galaxies, that were first observed and recorded by astronomers a long time ago. It’s like a really big book with a lot of pictures and information about these objects.
Things in space move around a lot and change over time, so the RNGC is updated every once in a while to make sure the information is still correct. The most recent update was made in 2009.
This catalogue is really helpful to astronomers because they can use it to identify and study different objects in space. It’s like a map that helps them navigate through the vast universe!